Active Region 1402, the same sunspot cluster that blew out a solar flare and caused all the ruckus last week, is still being feisty: just before rotating to the other side of the Sun, it erupted in an intense, pulsing solar flare that actually was much more powerful than the one that happened last Monday. This was an X2 class flare, making it more than twice as energetic as Monday's.
Happily, the flares were on the edge of the Sun's disk, so the bulk of the radiation was aimed away from the Earth, but it still makes for some pretty dramatic footage. Using helioviewer.org I created a video showing about 2.3 hours of the Sun as seen by NASA's Solar Dynamics Observatory. It shows the Sun in the extreme ultraviolet (at a wavelength of 19.3 nanometers if you wanna get geeky), where magnetic activity is seen easily. Watch the upper right corner of our friendly star... and make sure you make it HD and full screen.
Isn't that awesome? The flare got so bright the automatic software dimmed the rest of the Sun to compensate, giving you an idea of just how powerful these flares can be: at peak, they can give off several percent of the entire Sun's brightness in one small spot! I love how you can see it pulsing over the course of several minutes; I counted 10 separate flaring events. Each pulse was from a snapping of the Sun's magnetic field lines, a cascading series created when the first one went off and triggered the rest. And each released mind-numbing amounts of energy -- tens of thousands of times our entire planet's nuclear arsenal combined. Also, you can see the arcing loop around the flare site; that's plasma trapped in a field line. It erupts outward, but bear in mind the scale: it's several hundred thousand kilometers across, roughly the distance from the Earth to the Moon, and it blasts away from the Sun like the devil himself is after it.
Like I said: awesome.
You might have noticed the flare looked like an elongated diamond. That's not real! It's a digital artifact; what's happening is the flare got so bright it overwhelmed the pixels in the SDO detector. These collect light like a bucket collects rain. If too much light hits them, they overflow into the neighboring pixel. This flare was so bright it flooded the detector, and created that effect -- technically called blooming.
We haven't seen much of an effect from this flare -- just a minor radiation storm that's at the lowest end of the scale, nothing to worry about -- since it wasn't pointed at us. Had this been in the center of the Sun's disk, well. That might've given me my chance to finally see some aurorae from Colorado. Not this time, though, and sunspots generally don't last long enough to make it all the way around the Sun again (which takes about 30 days to spin once). But the Sun has a lot of magnetic energy still up its sleeve, and we'll be seeing more flares like this as we approach the peak of the cycle in 2013 and 2014.